this is an archetype that often arises from the human psyche: the guardian angel, caretaker, spirit-guide. In T.S.Eliot's 'Waste Land' there's a passage about travelers in extreme circumstances' sense that there is a 'third' one walking beside them but when they look, nobody. why are they showing themselves to you in a dream ...?

... maybe inviting you to start a conscious relationship with them ... (or with the 'inner' part of yourself they represent [all dream elements are 'parts' o the dreamer] ). y can 'work' with opening a dialogue with/ addressing them, for your 'spiritual growth' in general, thro meditation, imagin-ation, dreams ...

'and make themselves vulnerable'...why do u think they would feel that way? After all, they 'mean u well'/'care n look out for u'/are acknowledged and accepted by u..what's stopping u from 'going further', as in #2...do U perhaps have mixed feelings: vulnerable in part-afraid to move beyond mere acknowledgement..its implications?

.....u seems to know they're around, n to actually count on their being around...some sort of positive energy/vibe that u don't wanna 'push away', but that u're not sure u wanna 'bring closer' either?...